Catalyst reactivation



Aug- 25, 1942- B. EVERING ETAL 2,293,891

CATALYST REACTIVATION Filed Aug. 19, 1940 2 Sheets-Sheet 2 mi) L 3 l2 i620 2lb 28 PPDI/C?" GLL U/.S PEI? LB, CTLYS'T Patented 'Augg 25, 1942UNITED STATES PATENT FFICE CATALYST REACTIVATION Bernard L. Evering andEdmond L. dOuvllle,

Chicago, Ill., assignors to Standard Oil Company, Chicago, Ill., acorporation of Indiana Application August 19, 1940, Serial No. 353,210

8 Claims.

This invention relates to the recovery of aluminum halide catalysts andrelates more particularly to the reactivation of aluminum halidecatalysts degraded during the conversion of hydrocarbons.

The use of aluminum halide catalysts for the conversion of hydrocarbons,either alone or in the presence of such added promoters as hydrogenhalides, organic halides, etc., is well known. For example, aluminumchloride is known to promote the cracking of hydrocarbons, particularlyhigh molecular weight hydrocarbons such as may be found in kerosenes,gas oils, etc., to hydrocarbons of lower molecular weight; thepolymerization of normally gaseous olens to form higher molecular weightoleiins of gasoline or lubricating oil boiling range; the alkylation ofisoparainic or aromatic hydrocarbons with olefinic hydrocarbonsthroughout a wide boiling range; the isomerization of straight-chainhydrocarbons to branched-chain hydrocarbons; and numerous additionalconversion processes wherein hydrocarbons or mixtures of hydrocarbonsare converted to other hydrocarbons usually of more desirablecharacteristics commercially as regards configuration, boiling range,octane number, oxidation stability, etc. In practically all theseprocesses, the aluminum halide, such as, for example, aluminum chlorideor aluminum bromide, is gradually converted to an aluminumhalidehydrocarbon sludge. The exact mechanism of this conversion is notunderstood, but apparently the catalyst forms complex compounds with thehydrocarbons undergoing treatment and in so doing its catalytic activityis diminished or eliminated. The sludge varies from black, tarry orresinous matter to light red oils and, broadly speaking, the chemicalstructure defies analysis. Throughout this specication and claims, theterm aluminum halide-hydrocarbon sludge is intended to designate thereaction product of an aluminum halide with a hydrocarbon or hydrocarbonmixture.

It is also well established that fresh aluminum chloride or freshaluminum bromide is extremely active as a catalyst and that its use isoften deleterious because of the extremes to which it carries thereaction and the undesirable side reactions which it introduces andwhich cannot be controlled. This is particularly true in the case ofalkylation and certain isomerization reactions, It is often desirableLtherefore,

to modify the catalytic activity of the -aluminum halide catalyst and ithas been -discovered that the light red oil complexes which are quitemobile and fluid have the catalytic activity of the aluminum halidesufllciently modified to -be acceptable as catalysts but still retainsuilicient activity to promote the desired hydrocarbon conversion. Theexact composition of these red oil complexes is not known, but

yhydrocarbons with which it has formed a complex material.

It is an object of our invention to provide a' process for thereactivation of aluminum halide sludge. Another object of our inventionis to provide a process for the restoration of catalytic activity to analuminum halide catalyst spent as regards hydrocarbon conversion. Afurther object of this invention is to provide a process for therecovery of active catalyticy material from an aluminum halide sludge.An additional object of our invention is to provide a process forregenerating a spent aluminum halide catalyst for further use in theconversion of hydrocarbon material. Additional objects and advantageswill become apparent as the description of our invention proceeds, readin conjunction with the accompanying drawings which form a part of thisspecification, and in which Figure 1 represents a simplied flow diagramof a process embodying one example of our invention' and Figure 2 is agraph comparing an isomerization reaction with and without hydrogenregeneration of the catalyst.

Briefly stated, We have found that the catalytic activity of an aluminumhalide sludge can be substantially restored by contacting it withhydrogen, either alone or in the presence of a scribed by Yway ofexample in relation to a paraffin isomerization process employingaluminum chloride as the catalyst.

Referring now to the drawings: A feed stock from line II entersisomerization reactor I through line I2. As feed stock we can employ avirgin stock boiling within the range of from about 0 to 550 F.,suitably from about 30 to about 400F., and preferably from about 100 toabout 155 F., from any suitable source such as straight-run napthas fromcrudes, natural gasolines from natural gas or distillate wells, etc.Although aromatic and oleflnic hydrocarbons may be present, it isdesirable to carry out our process with a substantially saturated feedstock, free of aromatics and oleflns.

Catalyst enters through line I3 which joins line I2. As a catalyst wecan employ fresh anhydrous aluminum chloride or can employ an activecatalyst formed by the reaction between aluminum chloride and ahydrocarbon or hydrocarbon mixture, preferably one predominantlyparainic and/or naphthenic in nature. It is quite feasible for ourprocess to inaugurate the reaction using fresh aluminum chloride andthen as the reaction proceeds to replace the fresh aluminum chloridewith recycled sludge or re.- activated sludge, or a combination of anytwo or three of these catalysts. The isomerization reaction ispreferably carried out in the presence of a promoter, such as hydrogenchloride or an `organic compound yielding hydrogen chloride Vunder thereaction conditions, which enters through line I4. The catalyst can bepresent within the range of from about 5 to 65% by weight of theincoming feed stock, preferably from about to about 50% by weight, whilethe hydrogen chloride promoter is present to the extent of about 0.1 toabout 10% by weight of the charge, preferably about l to 3%.' Thereaction is carried out at a, temperature of from about 200 to 500 F.,preferably about 250 to 350 F., and at atmospheric or superatmosphericpressures, for example, from about 0 to about 500 pounds per square inchgauge pressure, or at least under such conditions that the reactants arein the liquid phase. As illustrated, the reaction can be carried out incoils I5 in reactor I0. The catalyst, feed stock and promoter areintimately mixed as they pass through line I2 to coils I 5, and theturbulent flow through the coils insures continued intimate contact ofthe reactants. Mixing means (not shown) can be inserted in line I2, orany other suitable means for obtaining intimate contact -between twoirnmiscible or slightly miscible fluids can Abe employed. For example,mechanical stirrers can be substituted, or the reactor can -be fittedwith a system of baiile plates. Turbo mixers, jet injectors, etc. canalso be used. The time of contact can range from ve minutes to twohours, preferably about one hour, and will depend upon the temperatureat which the reaction is carried out and the catalyst concentration.

The reaction chamber can be maintained at the proper temperature byemploying a suitable temperature-control -mediun1, etc., which flowsthrough reactor I0, entering through line I6 and discharging throughline I1. It is also possible and usually desirable to heat the incomingfeed stock (by means not shown) to the desired temperature orthereabouts and also -to elevate the temperature of the catalyst withinthe approximate range desired to initiate the reaction.

The hydrocarbons together withthe catalyst and promoter are withdrawnfrom reactor I0 by line I8 and directed to settler I9,wherein aseparation between the hydrocarbons and the catalyst takes place, thecatalyst settling to the bottom of the settler I9. The hydrocarbons arewithdrawn overhead through line 20 and can be directed to fractionator2| wherein the hydrogen chloride and any normally gaseous hydrocarbonswhich may have been formed during the reaction are taken overheadthrough line 22 and may be discarded by opening valve23 in line 24 orrecycled to the isomerization reactor I0 by opening valve 25 in line 26which joins line I4. This will be particularly desirable in case thereare major quantities of hydrogen-chloride remaining from the reaction.The products from the isomerization reaction of any desired boilingrange, preferably of a boiling range suitable for use as a motor fuel oran aviation gasoline, is withdrawn through line 21 while heavierhydrocarbons can be withdrawn through line 28.

The separated aluminum chloride-hydrocarbon sludge is withdrawn fromsettler I9 through line 29. In case it still retains a sufficient amountof activity it can be recycled directly to isomerizer I0 by openingvalve 30 in line 3I which joins line I3 leading to reactor I0. If,however, it has become spent as regards the promotion of isomerizationit can be withdrawn by opening valve 32 in line 33 and sent toreactivator 34. Alternately itis quite possible to recycle a part of thecatalyst sludge from settler I3 and to reactivate the remainder by theproper adjustment of valves 30 and 32 in lines 3| and 33 respectively.Preferably, the catalyst is withdrawn for regeneration while stillmobile and fluid, not only because of greater ease in handling, but alsobecause it can be regenerated more rapidly and easily.

The aluminum chloride sludge is intimately contacted in reactivator 34with hydrogen which enters through line 35. The reactivation can becarried out at temperatures within the range of from about 200 to about500 F. and under a pressure of from about 40 to about 400 atmospheres ofhydrogen. In all events, however, the conditions of temperature andpressure are so selected as to preclude the distillation or sublimationof the aluminum chloride from the sludge, or the coking or destructivehydrogenation of the hydrocarbon material in the sludge with theliberation of aluminum chloride therefrom. If desired, a small amount ofa hydrogen halide, such as hydrogen chloride, can be used, which entersthrough line 36. The hydrogen, hydrogen chloride and the catalyst sludgeare intimately contacted in reactivator 34 by any suitable means, suchas a stirrer 31, for a period of time which may range from 0.5 hour to10 hours, preferably 3 hours, depending upon the type of sludgeencountered, and the reactivated sludge together with unreacted hydrogenwithdrawn through line 38 which leads to separator 39. In separator 39the hydrogen can be released overhead through line 40 and discarded byopening valve 4| in line 42, but preferably is recycled to reactivator34 by opening valve 43 in line 44 which joins line 35. During the courseof the reactivation a certain amount of hydrocarbon material will befreed from the sludge and this can be withdrawn through line 45.Generally speaking, less than 4% hydrogen, based on the weight ofcatalyst, will be consumed.

The reactivated sludge, now substantially restored in activity, iswithdrawn from separator 39 through line 46 and can be sent to storageby opening valve 4'1 in line 48, but preferably is returned to theisomerization reactor by opening valve 49 in line 50 which joins line I3leading to reactor l0.

As an example of our process. we have isomerized a light naphtha. withan aluminum chloride-hydrocarbon complex formed during the reaction withand without hydrogren regeneration of the catalyst. The results are setforth in Tables I and II, Table I being data obtained withoutregeneration between runs and Table II containing data obtained whenusing hydrogen regeneration. A comparison is also shown graphically inFigure II in which the reaction velocity constant k is plotted againstgallons of 4product obtained. per pound of catalyst. Perhaps the moststriking measure of catalyst activity in isomerization is the increasein octane number of the product. However, the octane number is not onlya function of the catalyst activity'but also of the contact time, whichmust be corrected, since the time is varied appreciably in the earlystages in order to avoid overtreating the feed where t=time in hoursZ=equilibrium octane number minus number of feed.

ACFR-M=octane number of product minus octane number of naphtha. Theequilibrium octane number" is the highest constant octane numberobtainable on any given feed stock at a octane specific temperature andis not affected by in- I creased time of contact or increased ratio ofamount of catalyst to amount of oil. 'I'he catalyst activity is usuallysuch that the octane number of the product is not as great as theequilibrium octane number so that ACFR-Mis less than Z.

The constants thus calculated are only relative but are preferably validfor comparison purposes.v

Table I Run . Summary A B C D E F G H Charge:

Light naphtha, liters 1.0 0.78 0.78. 0.78 0.78 0.78 0.78 0. 78 6. 32Catalyst, wt. of feed 10.8 l 1.69 Activator, wt. of feed 3. 0 2. 7 2. 72. 7 2. 7 2. 7 2. 7 2. 7 2. 7 Gals. L. N. processed/lb. catalyst l. 73.0 4. 3 5. 6 6.9 8.2 9.5 10.8 10.8` Conditions:

Temperature, F 300 316 330 332 332 330 332 330 R glmlact time, hrs 0. 130. 15 0. 33 l. 33 2. 50 2. 75 3. 75 4. 42 l 1. 92

es s:

Vol. yield (output basis, (J4-free) 94. 2 Octane number-CFR-M (C4-free)74. 5 77. 2 73.9 74. 5 73. 4 74. 9 A. P. I. gruvity 84. 1 84. 3 83. 884. 1 84. l 84. 0 R. V. P., lbs/sq. 12.0 Isobutane g 17.0 27.4 19.6 18.715.0 33.7 Wc. red 011 (based on feed) 2.4 Reaction velocity constant k0.45 0. 0. 16 0. 15 0. 09 Weight balance, percent 98. 3

1 Actual catalyst concentration during each batch run, 10.8%. l Average.3 Wt. weight based on feed.

Table Il Run Sum-

. mary A A-R-B B B-R-C C C-R-D D D-R-E E E-R-F F F-R-G G G-R-H H H-R-J.T

Chaiett ha.

na a iims .l 1.o 1.o 1.0 1.0 1.o 1.o 1.o 1.o 1.o 9.o

t Camgt `10.8 11,2 A tivator wt. l

9%01 feeiLg.. 3.1 (5.0) 3.1 (5.0) 3.0 (5.7) 3.1 (6.0) 3.1` (6.0) 2.9(6.0) 3.0 (6.8) 3.1 (6.0) 3.1 3.1 Gals. L. d ,lg

rocesse gatalyst 1.7 3.4 5.1 6.8 8.5 10.2 11.9 13.6 15.3 16.3 Conionls:

ress. 1bs./s.pm 1,000 1.000 1.000 1.000 1.000 1.000 1,000 1,000

erature y Tllp. 1. 310 318 312 320 330 325 329 324 330 323 324 321 377320 328 324 325 y 325 Co t time I Run Sum- :A A-R-B By B-R-C y CvB-D DD-'R-E -E EvR-F F vF-R-Gf G G-R-H E H-R-J J' ary Results:

Vol. yield (output basis rtree) 96.8 tane number-CFR-M (C4-free)- 79.576. 5 75.1 74.4 77.0 A. P. I gravity 84` 1 83.8 83.2 83. 2 83.5 R. V.P., lbs./

sq. in 12.3 Isobutane, g 24. 4 17. 5 15. 7 3. 4 Wt. red oil (based onfeed). i.-. 0.4 Hydrocarbon 1 rcmoyedlrom cat., g 20.0 9.9 15. l 5 3 8.14. 2 8. l 7.6 H2 consumption, cu. it--. 2.3 0.69 0.90..-- 1.08 1. 341.24 1. 43 1.21 Reaction velocity, constant 13.1 8.6 1 6 1.6 1.1 1.00.68 0.74 0.65 Weight balance, 96.

l Actual catalyst concentration during each batch run of the life study,10.8%.

z Wt. based on leed.

runs A in Table I and A in Table II the complex from each run being usedin each succeeding run throughout the tests. The regeneration in TableII is indicated by lthe heading, e. g., A-Rf-B. indicating thatregeneration took place between run A and run B.

It will be obvious from the above that the catalyst life wasconsiderably prolonged by the use of hydrogen regeneration between runs.It was thought necessary in Table I to discontinue after run H becausethe catalyst was suiciently spent to preclude any further effectivetreatment. This yielded only 10.8 gallons of product lper pound ofcatalyst. It was necessary in Table I to increase the contact timecontinuously in order to obtain a product having an octane numbercomparable to the octane number of the preceding runs, which was nottrue in Table II. The reaction velocity constant of Table 1I wasconsistently higher throughout than in Table I. Moreover, the catalystat the end of the runs in Table II was still capable of beingregenerated for further catalytic activity with lowl contact times, inaddition to the fact that the volume of products produced was markedlyhigher than when no regeneration was employed. We have thus shown thatby reconverting a spent or partially. spent aluminum halide-catalyst tothe form of a mobile hydrocarbon complex, we can reuse it catalyticallyfor repeated conversions, thereby increasing the yield per unit ofcatalyst extensively. We can also employ shorter contact times, therebydecreasing `the time required for the production of a given amount ofproduct.

Although vwe have illustrated our process in reference to anisomerization reaction, itfshould be understood to be equally applicableto other hydrocarbon conversion processes, such as polymerization,condensation, alkylation, etc., which Ainvolve` e use of an aluminumhalide, (particularly the hloride or bromide) as catalysts and duringwhich the catalyst is deteriorated or spent by the formation of analuminum halidehydrocarbon sludge.

Our process is particularly applicable to the regeneration of aluminumhalide-hydrocarbon sludges from hydrocarbon conversions carried out atrelatively low temperatures as, for example, temperatures less than 550F., and preferably at temperatures less than 350 F. Generally speaking,sludges formed at these temperatures do not exhibit coky or brittlecharacteristics and are much more easily regenerated. It becomes highlyadvantageous to regenerate rather than recycle at some minimum catalystactivity, which can be determined for each particular hydroqarbonconversion process. For example, in isomerization of the type describedherein, it is desirable to regenerate before the reaction velocityconstant lc falls below 0.5 and preferably before it falls below 1.0.Similar minimum constants can be determined for alkylation andpolymerization reactions. To do this it is usually desirable to use aportion of the spent catalyst from the polymerization or alkylationreaction to isomerize a. hydrocarbon mixture of known equilibrium octanenumber and from the increase in octane number thus occasioned by thespent catalyst determine the reaction velocity constant 1c for the spentpolymerization or alkylation catalyst.

For the sake of simplicity and clarity we have omitted various detailsas regards pumps, heat exchangers, valves, automatic control means,etc., the use of which will be. readily understood by one skilled in theart. We have also illustrated our process vas having one reactor and oneregenerator, but it is fully contemplated that multiple reactors andregenerators will be used, either in series or in parallel.

Itis also equally suitable to carry out our process batchwise in asingle reactor, the ow of fresh feed and recycle stock being shut off,the hydrocarbon material separated from the catalyst, and the catalystsubjected to hydrogen in the presence, if desired,of hydrogen chloride,

under the above-named conditions of time, tem-v -catalyst whichcomprises regenerating said aluminum halide-hydrocarbon sludge withhydrogen in the presence of a hydrogen halide and in the substantialabsence of other regenerating agent under conditions of elevatedtemperature and contacting said hydrocarbons of gasoline boiling rangewith a catalyst comprising a fluid alumielevated pressure adapted topromote the restoration of said aluminum halide sludge to an activemobile liquid aluminum halide-hydrocarbon complex catalyst.

2. A process for the recovery of active catalytic material from analuminum halide-hydrocarbon sludge formed during the conversion ofhydrocarbons in the presence oi.' an aluminum halide catalyst whichcomprises regenerating said aluminum halide-hydrocarbon sludge withhydrogen in the presence of a hydrogen h-alide and in-the substantialabsence or other regenerating agent under a pressure with the range offrom 40 to 400 atmospheres and at an elevated ltemperature adapted topromote the restoration of said aluminum halide sludge to an activemobile liquid aluminum halide-hydrocarbon complex catalyst.

3. A process for the recovery of active catalytic material from analuminum halide-hydrocarbon sludge formed during the conversion oflhydrocarbons in the presence of an aluminum halide catalyst whichcomprises regenerating said aluminum halide-hydrocarbon sludge withhydrogen in the presence of a hydrogen halide and in the substantialabsence of other regenerating agent at a temperature with the range offrom 200 to 500 F. and under a hydrogen pressure of from 40 to 400atmospheres.

4. A process according to claim 1 in which the aluminum halide comprisesaluminum chloride.

5. In a process for the conversion of hydrocarbons employing an aluminumhalide catalyst in the absence -of added hydrogen, the improvementcomprising withdrawing the spent aluminum halide catalyst from theconversion step, regenerating said spent catalyst with hydrogen in thepresence of a hydrogen halide and in the substantial absence of otherregenerating agent under conditions of elevated ,temperature andelevated pressure whereby the activity o'i said spent catalyst issubstantially restored without formation of free aluminum halide, andreturning said restored catalyst to said conversion step.

6. In a process for the conversion of hydrocarbons of gasoline boilingrange to hydrocarbons of improved octane number which comprises numhalide-hydrocarbon complex in theabsence or added hydrogen and in thepresence of a promoter comprising a hydrogen halide under conditions oftemperature, pressure and time of contact adapted to promote theisomerization of at least a substantial portion or said hydrocarbons ofgasoline boiling rangeto hydrocarbons of increased octane number,whereby said catalyst is converted to an aluminum chloride-hydrocarboncomplex of decreased catalytic activity, the improvement comprisingseparating said hydrocarbons of increased octane number from the spentcatalyst, regenerating said spent catalyst with hydrogen in thesubstantial absence of other regenerating agent under conditions oftemperature, pressure and time of contact and in the presence ofhydrogen chloride whereby the activity of said spent catalyst issubstantially restored and contacting said restored catalyst withfurther amounts of said hydrocarbons of gasoline boiling range for theproduction of further quantities of hydrocarbons of improved octanenumber.

7. A process for the restoration of catalytic activity to an aluminumhalide-hydrocarbon complex spent as regards the promotion of thecatalytic conversion of hydrocarbons which comprises regenerating saidspent complex with hydrogen in the presence of a hydrogen halide and inthe substantial absence or other regenerating agent under a pressure offrom about 40 to 400 atmospheres and at elevated temperatures sufficientto effect the restoration but insufficient to recover aluminum halidefrom the complex.

8. In a process for the conversion of hydrocarbons in the presence of acatalyst comprising the reaction product of a substantially saturatedhydrocarbon and aluminum chloride wherein said catalyst is reduced inactivity and converted to a sludge, the improvement comprisingregenerating said catalyst sludge substantially free o! reactinghydrocarbons with hydrogen in the presence of hydrogen chloride and inthe substantial absence of other regenerating agent at an initialpressure of about 1000 pounds per square inch at a temperature withinthe range of from 318 to 325 F'. for a period of about three hourswhereby the activity of the catalyst for promoting said conversion issubstantially restored and using said restored catalyst for theconversion of further quantities of hydrocarbons.

BERNARD L. EV'ERING.. EDMOND L. DOUVILLE.

.to thev record of the cama in the Patent Office.

GERTIAF'ICATE oF cormlacnom retent ne. 2,295,891, August 25, 15u-2,

BERNARDl L. EVERING, mi AL..

It .is hereby certified that error appears in the. printedspecificati-on ofthe above numbered patent requiring correction a'sfollows: Page 5, Table I-I, 'under "Run G", line 2 from bottom of page,iov'r l57.7" read .4527--5- page 1|.,.same Table II continued,undor'sxmnnary, ,last line thereof, for "96." read 96.21; page 5, firstcolumn, linea 25 and 56, claims 2 and 5 respectively, for with" reed'-w1th1`n; and that the said. Letters Petent should be read with thiscorrection therein that ,the ,same may conf-om signed end seeled this29th du' er septemter, Aem-19h12.

. Henry Van Andale, (Seal) f Actin: Commissioner of Patents.

